When producing from, injecting into or maintaining a downhole well, a need for opening or closing flow as well as directing fluids of different densities arises.
WO 2013/070235 discloses an apparatus for autonomously controlling fluid flow in a subterranean well, the fluid having a density which changes over time. An embodiment of the apparatus has a vortex chamber, a vortex outlet, and first and second inlets into the vortex chamber. Flow into the inlets is directed by a fluid control system which has a control passageway for directing fluid flow as it exits a primary passageway. A movable fluid diverter positioned in the control passageway moves in response to change in fluid density to restrict fluid flow through the control passageway. When fluid flow through the control passageway is unrestricted, fluid from the control passageway directs fluid exiting the primary passageway toward a selected vortex inlet. When flow through the control passageway is unrestricted, flow from the primary passageway is directed into the other vortex inlet.
US 2008/041580 shows an autonomous flow restrictors for use in a subterranean well. An apparatus is disclosed for use in a well wherein both oil and gas are produced. The apparatus includes multiple flow blocking members having a density less than that of the oil. The members are positioned within a chamber with the members increasingly restricting a flow of the gas out of the chamber through multiple outlets. Another apparatus is disclosed for restricting production of at least one undesired fluid which has a density different from a density of a desired fluid. The apparatus includes at least one flow restrictor and at least one bypass flow restrictor. The bypass restrictor may have a greater restriction to flow therethrough as compared to the other flow restrictor. The apparatus further includes multiple flow blocking members operative to increasingly restrict flow of the undesired fluid through the flow restrictor in response to an increased proportion of the undesired fluid.
WO 2014/081306 discloses an apparatus and a method for controlling fluid flow in or into a well, wherein the apparatus comprising: at least one housing having: an inlet; and at least one outlet, one of which is arranged in a top portion or a bottom portion of the housing when in a position of use; and a flow control means disposed within the housing, the flow control means having a density being higher or lower than a density of a fluid to be controlled, and a form adapted to substantially block the outlet of the housing when the flow control means is in a position abutting the outlet.
US 2013/068467 discloses an inflow control device that controls the rate of fluid flow from a subsurface fluid reservoir into a production tubing string. The inflow control device includes a particulate screen to remove particulate matter from the reservoir fluid, and at least two flow restrictors. The flow restrictors are positioned on circumferentially opposite sides of the inflow control device and are connected by an isolated fluid passage. The flow restrictors limit the flowrate of reservoir fluid when the reservoir fluid has a high water or gas-to-oil ratio. The inflow control device also includes at least one pressure drop device that generates a pressure drop for the reservoir fluid in response to fluid pressure in the reservoir. The inflow control device also includes a choking apparatus that allows the flow of reservoir fluid to be shut off and the particulate screen cleaned while the inflow control device is in place in hole.